The present invention relates to auto-ignition, booster, and primary gas generating compositions. As known in the art, gas generators are typically provided with an auto-ignition composition that in the event of a fire ignites responsive to a desired threshold temperature. As a result, the primary gas generant is ignited prior to melting for example, thereby safely igniting the primary gas generant composition to inhibit or prevent the likelihood of an explosive event once the gas generant begins to combust. Another composition typically employed is the booster composition, functioning to rapidly increase the pressure in the gas generator so that a primary gas generating composition burns with optimum efficiency. Of course, the primary gas generating composition is employed as its name indicates: for production of useful amounts of gas in any vehicular protective context for example, such as airbags, seatbelt pretensioners, and so forth. Other gas generating applications are also contemplated as will be appreciated by those of ordinary skill in the art.
An ongoing challenge is to simplify the manufacture of a gas generator by reducing the constituents required in the production thereof. As explained above, in many gas generators used in vehicle occupant protection systems, several discrete compositions are provided to serve correspondingly discrete functions. These compositions often include a primary gas generating composition that when combusted is employed to provide sufficient quantities of gaseous products to operate the associated restraint device, such as an airbag or seatbelt pretensioner. A booster composition is utilized to elevate the pressure and heat within the gas generator prior to combustion of the primary gas generant, thereby creating favorable conditions within the inflator for acceptable combustion of the primary gas generant. Of course, still yet another composition is the auto-ignition composition employed to provide safe combustion of the other compositions in the event of a fire. The auto-ignition composition is designed to ignite at temperatures below the melting point of the primary gas generant for example, thereby ensuring the controlled combustion of the primary gas generant, as opposed to an explosive reaction perhaps.
The use of potassium chlorate within an auto-ignition composition has been considered given the auto-ignition properties of this oxidizer. Furthermore, carboxylic acid in combination with potassium chlorate typically provides a desired auto-ignition temperature of 200 degrees Celsius or less. Nevertheless, these types of compositions typically do not provide anything but auto-ignition function when employed in gas generators used in vehicle occupant protection systems, for example.